(a) Field of the Invention
The present invention relates to low-voltage phosphor material having a high level of brightness and a manufacturing method thereof. More particularly, the present invention relates to a low-voltage phosphor material and a manufacturing thereof in which a metal is added to the phosphor material to prevent oxidation of the phosphor material and reduce surface charge of the same such that brightness of the phosphor material increases.
(b) Description of the Related Art
Low-voltage display devices utilizing voltage of 1 kV or less to radiate phosphor material include the FED (field emission display), the VFD (vacuum fluorescent display) and others. FEDs utilize the well-established cathode-anode-phosphor technology built into full-sized CRTs, and use this in combination with the dot matrix cellular construction of LCDs. However, instead of using the single bulky tube of the CRT, FEDs use tiny `mini tubes` for each pixel such that the display can be built in approximately the same size as an LCD screen. The VFD is a self-radiating display in which electrons continuously emitted from a filament, which functions as the electron gun in a CRT, are controlled by a grid electrode and an anode electrode to collide with phosphor material on the anode such that the phosphor material is radiated. The VFD offers wide viewing angles and is able to be driven using only a low level of voltage. Accordingly, the display can be used for many applications.
With regard to VFDs, the phosphor material used in the same includes a green ZnO:Zn based compound, and (ZnCd)S and ZnS based compounds of other colors. The green ZnO:Zn phosphor material has a high level of brightness compared to the phosphor material of other colors since it is highly efficient in the radiation of light. That is, the brightness of the phosphor material of other colors for the (ZnCd)S based compound and the ZnS based compound is only 5 to 20% that of the brightness of the green ZnO:Zn phosphor material. Accordingly, the phosphor material of other colors has a far lower level of brightness when compared to the phosphor material of the ZnO:Zn based compound. As a result, the majority of the phosphor material used in VFDs is the green phosphor material, while the phosphor material of other colors is used only minimally. With better image quality being dependent partly upon a high level of brightness, much institutions are conducted to improve the brightness of the phosphor material used in displays.
There is a need to improve the brightness of low-voltage display devices that use phosphor material.